Automatic telephone system.



E; NEUHOLD.

AUTOMATIC TELEPHONE SYSTEM.

' APPLICATION FILED 0012a, 1010.

Patented Nov. 12,1912.

' UNITED STATES PATEN @FFICE.

ERW IN NEUHOLD, OF FBIEDENAU, NEAR BERLIN. GERMANY, ASSIGNOR T0 FIRMAUEUTSCHE TELEPHONWERKE, G. M. B. 11.. GE BERLIN, GERMANY.

AUTOMATIC TELnP HoivE SYSTEM.

Specification of Letters Patent.

PatentedNov. 12, 1912.

p 7 Application filed October 8. 1910. Serial No. 586.019.

To all whom it mag] concern:

Be it known. that I, Eiiwt x NEUnoLn, engineer, a subject of theKing ofHungary, andresident of Friedenau, near Berlin. Ger- I many, haveinvented certain new and usei ful Improvements in Automatic TelephoneSystems. V I

The'subj'ectof the invention is an unpIOVEIDQIl'D in automatic telephonesystems which makes it possible to effect the release of the speakingconnections by simply break- 5 ing the circuit in hanging up therecelver, 1

and further to operate the control magnets of the selectors by means oftwo simple line relays 1n such manner that it is not neccrcases andincreases of current and a subsequent lnterruption of the circuitoccurring i ceiter to its movable hook. The two con trol relays thensimultaneously release their armatures which now by suitable cooperationclose the circuit of the release magnet or magnets.

In the drawing a few examples of construction according to the inventionare illustrated which differ in the way in which the relay armaturescooperate to etlect the release.

A double line 1. 2. extends from the battery b of the exchange to thesubscribers station which is connected in the usual manner for centralmicrophone. supply and is provided with a microphone "1-, a receiver 25,essary either to earth the lines'at the subscribers station nor tohavethe response of the relays i etarded by retarding devices. '5

According to the invention the controlling device referred to isoperated by the subscriber through a series of alternate deimmediatelyafter the previous wtarkeningot' the current. This regulation of thecurrent is suitably ettected by means of an automatically operatingspring driven contact device at the'subscribers station and is repeatedas often as is necessary to correspond with the digits of the desiredsubscribers number. or to correspond with the operations required at thecentral station for the connection of the desired subscriber.

The periodic alterations of current set 1 the conductors an inductioncoil '11 and a bell to with a condenser c.

The currentsending device consists of a toothed wheel a which has aseries of teeth of equal size and atv the end of this series a largerstepped tooth: this when rotated sets the switch a in oscillation. Theback con tacts 3, -l. of this switch normally short circuit theresistance (Z and are broken in the most open position oi theswitch sothat "l. i are interrupted. the

' switch is brought into the most open posithe armature of one of thecontrol relays in i oscillation and the breaking of connections whenthis armature has been released for 1 the last time also releases thearmature of the other control relay which up till then ment the smallteeth of (2' insert the resistance relay for example controls thelifting magnet ofthe selector while the other armature completes thecircuit of the turning magnot once and this magnet is then connected Iare excited by current rlowing over conducin known manner either intothe circuit of an interrupter so that the further turmng of theselectormay go on automatically. or 3 into the place of the lifting magnet sothat .ctt'ected by interruption of the current which "flows over; thelines during the eonversa tion..which current may suitably supply the'1n1crophonesby restoration of the re tion by the upper step of thelarge tooth ot the wheel a after the smaller teeth and the lower step ofthe large tooth have brought the switch into intermediatepositions inwhich only the contact 3 is opened while contact -t remains closed. Thewheel a is turned in the direction of the arrow against the. action oi aspring and during this movctor 1. contact 3. microphone m. the frontcontact 5 on the receiver hook and conductor 2. and attract theirarmatures. At first no current impulse passes over the armatures. If.however. the resistance d is inserted in the conductor by the action ofthe current sender a, the relay A lets its armatures fall back acorresponding number of times and so period-:ally closes over its backcontact T the circult Z), 6, E, I 8, 9, 1D in whicn IS the liftingmagnet H of the selector, and the selector is consequently lifted acorresponding number of steps. The circuit of the auxiliary slow actingrelay 1' is at the same time completed over the front contact 12 of bthroughthe back contact 11 of a, this at 'mains in the unattractedposition and the re: I lease of the armature of B occurring through theinterruption of the conductor closes its back contact 13. At the sametime contact 12 is opened but the relay r remains excited over theretaining contact 14 of its armature and over contact 11 of A. If thiswere not the case the release magnet It would be excited over 13, 15, 6and would release the selector prematurely. On the contrary the closingof the back contact 100i B causes the turning magnet D of the selectorto re ceive current over 10, 16, 17, 18, D, (i, and this magnetresponds. By this means as already mentioned the selector is. turned onestep in known manner (not illustrated) whereupon the switch operated bythe selector shaft connects the turning magnet I) either (at the groupselector) to a conductor carrying a periodic current by which means theselector is automatically moved on, or (at the line selector) to theconductor 19 in place of the lifting magnet H, so that it may be furthercontrolled by the subscriber in desired manner. These operations arewell known in automatic. telephone exchanges and need thus no furtherdescription. When the device a has run back the microphone circuit isagain completed over the line so that during the conversation the relaysA and B are excited. At the end of the conversation contact 5 is openedthrough the hanging up of the receiver on its hook, the

lines 1 and 2 are interrupted and thus there results a sudden fallingbackof the armatures of both relays A and B. The relay r is not nowexcited since atthe same time as y or even before the contact 11 on thearmature A is closed, the contact 12 on the armas ture B is opened.Consequently contact 15 remains closed and current now flows over 10,13, 15, R and 6 and excites the release magnet R. This causes theselector to return in known manner to its position of rest. As the arrow20 indicates, during the production of the speaking connection therelease magnets of the other selectors used are also automaticallyconnected in known manner to the contact 15 sothat they are allsimultaneously excited and all the selectors used are simultaneouslyreleased.

In Fig. 2 is illustrated a solution of the problem in which an auxiliarydevice mechanically actuated by both relay armatures is used instead ofthe auxiliary relay r, this 24 is attracted since in that case the crossarm turns about the pivot 26 toward the side of the fallen arniature. Itthus slips below the armature 25 and is. restored to the centralposition by the springs 27. The arm :23 remains ahovethe attractedarmature 24. This latter as it rises and falls from time to time brushespast the arm turning it alittle about the pivot 26 without lifting theWeight g. If the armature 25 is attracted also it passes beneath theleft hand arm 22 as well. (In the form of connections according to Fig.1 both armatures are simultaneously attracted at the beginning so thatthe weight 9 simply sinks with them.) If now both relays aresimultaneously deprived of current, since the cross arm cannot deflectthe armatures they carry the weight up with them and close the releasecontact 15. If on the other hand the armature of B only falls when thearmature of A has already returned to the position of rest, the crossarm of g deflectsmnd the contact 15 remains open. This is what happenson the inter-- ruption of the line at contact 4 of Fig. 1.'

In order that the arms 22, 23 may be rengaged when both armatures aresimultaneously attracted again after the interruption of the lines as isnecessary for the subsequent raising on release above described, thearms are pivoted and spring pressed in such a way that they can deflectdownward but not upward if the two armatures press on them with equalforce.

Fig. 3 shows another form of the mechanical auxiliary device. In thiscase the armatures themselves press down a hollow body n slidingfrictionally in the guide m when they are both simultaneously attracted.The release contact 15 is thus opened. When the two armaturessimultaneously fall back a cross bar pivoted on the rod 0 follows themunder t e attraction of spring k and this cross arm striking against thespring projections 11 on body n lift this latter so that contact 15 isclosed. This lifting does not occur if the armatures move only one at atime for then the cross bar 1) sets itself in sloping osition. (The rod0 slides loosely in n.) T e projections 12 are spring mounted in orderthat the cross rod 72 may again engage under them when the armatures aresimultaneously attracted. This corresponds to the pivotal mounting ofthe arms 22, 23 in Fig. 2.

The invention is not restricted to the form l' t of constructionIllustrated for a great number of dlflejrent forms are possible: The

operation of the line relays A. and B inac- 5 cordance with theinvention as well as that of the auxiliary relay 1'- or of an equivalentauxiliary electrical device may be. secured not only by the resistancevariation of the lines 1,-2- described but also for example b earthingthe separate lines so that the inof operation also. r

.I claim 1 In an automatic telephone system: an

vention may be suited to this older method exc ange containing a.selector provided turning magnets over the contacts and armatures ofboth said relays with the common battery, lines for connecting eachsubscribers station with the exchange and containin-g in'the latter thesaid two relays and the common battery, a plurality of subscribersstations each containlng'in series the usual subscrrbers set and aswitching apparatus adapted to connect the subscribers lines eitherdirectly or over a resistance or to dis- 30, connect said lines,substantially as and for the purpose set forth.

2, In an automatic telephone system an exchange containing a selectorprovided with a lifting, a turning and a release magnet, two relayscoordinated to each subscribers station, a battery common for allrelays, conductors connecting the lifting and turning magnets over thecontacts and arma tures of both said relays with the common 40 battery,means for opening the circuit of the release magnet of a selector, whenone or both coordinated relays attract their armatures and for closingsaid circuit only,

if the armatures of both relays return simultaneously into theirpositlon of rest, lines for connecting each subscribers station with theexchange and containing in the latter the said two ,relays and thecommon batter-y, a plurality of subscribers stations each containing inseries the usual subscribers set and a switching apparatus adapted toconnect the subscribers lines either directly or over a resistance or todisconnect said lines, substantially as and for the purpose set forth.

3; In an automatic telephone system an exchange containing a selectorprovidedwith a lifting, a turning and arelease magnet, two relayscoordinated to each subscribers station, a battery common for allrelays, conductors connecting the lifting and turning magnets over thecontacts and armatures of both said relays with the com mon battery, athir relay controlled by said two relays and ad pted to open the circuitof the releabe magnet of a selector when one or both cdordinated relaysattract their armatures and for closing said circuit only, if thearmatures of both relays return sis multaneously into their position ofrest, lines for connecting each subscribers station with the exchangeand containing in the latter the said two relays and the common battery,a plurality of subscribers sta tions each containing in series the usualsubscribers set and a switching apparatus adapted to connect thesubscribers lines either directly or over a resistance or to disconnectsaid lines, substantially as and for the purpose set forth.

In testimony whereof I aflix my signature in presence-0f two witnesses.

ERWIN NEUHO-LD. Witnesses:

HENRY HASPER, VVOLDEMAR HAUPT.

Copies of this patent may be obtained for five cents each, byaddressing'the Commissioner of Patents,

Washington, D. C.

